Process of manufacturing adhesive blends of sodium nitrate and ammonium nitrate for explosive purposes



Patented den. 55, .llZh.

wintraar at. noun, or sna'r'rnn, wnsnmoron'.

PROGESS, GT3 MANUFACTURING ADHESIVE BLENDS OF .SODI'UEE NITBATE AND AMHGNIUM NZTBATE FOE EXPLOBIVE PURPOSES.

No Drawing.

T 0 all whom it may concern:

Be it known that 1, WILLIAM M. Dunn, a citizen of the United States, residing at Seattle, county of King, and State of Nashington, have invented a certain new and useful Process of Manufacturing Adhesive Blends of Sodium Nitrate and Ammonium Nitrate for Explosive Purposes, of which the following is a full, clear, and exact descri tion.

ll y invention relates to the process, and the product of the process, of manufacturing blends of sodium nitrate and ammonium nitrate wherein, in general, the particles of sodium nitrate have adhering to them sub stantially equal or lesser masses of ammonium nitrate. This condition of intimate and adhesive contact of the two salts, during the explosion of compositions of which they are ingredients, promotes a. mutual and beneficial eiiect not obtainable to the same degree, when the two independent salts are mingled mechanically in powders.

The chief object of my invention is to obtain very inexpensive powders especially adaptable to conditions of stump-blasting and the like.

It is well known that when independently powdered sodium nitrate and ammonium nitrate are added to wood meal, the compositionsthus obtained are practically worthless as blasting powders. I have found that when liquid nitrotoluenes, so low in concentration as 5%, are added to these coinpositime, other compositions are obtained that are also practically worthless. However, on the other hand, I have found that when the two salts are rst powdered and then are wholly or partly melted together, and the blended mass thus obtained is cooled and repowdercd, I can mix it with wood meal and 5% of nitrotoluene so as to obtain readily detonating compositions.

The enhanced explosive properties of such blends of the nitrates of sodium and ammonium, therefore, not" only is demonstrated but can be accounted'for by the following observations. On the one hand, it is well known that powdered sodium nitrate in explosive compositions is very likely, during combustion and detonation. to melt and segregate in drops of such size that detonation is retarded or is prevented. Owing to this tendency, compositions of sodium nitrate, containing an insufficient sensitizing com- Application filed octane! 13, 1924;. Serisl N0. MBJBBQ.

ponent, tend to burn Without detonating and the charge may be lost in this manner in the blast hole. Furthermore, on account of of its high thermal and oxidizing efiects in compositions of which it is an ingredient, sodium nitrate contributes a den erous hazard to manufacture and storage. 11 the other hand, during combustion and detonation, ammonium nitrate evolves gases, shows little or no tendency to melt and segregate, and exerts an inhibitory effect on simple combustion. Furthermore, like sodium "Iritrate, it is an oxidant, but, unlike sodium nitrate, it itself is a. powerfully detonating material.

Now when these two nitrates are combined in minute and intimate contact, as set forth in this specification, so that their independent kindling and detonating properties are 'mingled, beneficial explosive effects are obtained. This can be demonstrated as described above or by measurements in the sand bomb or by the mere heating of their mixtures-the melted mass is observed to froth and foam and thus the ammonium nitrate counteracts a tendency of sodium nitrate to film into compact masses. Furtheremore, the blends and its mingled compositions are found to difier from simple nurtures in density, by hygroscopy and ease of lgnition.

The novelty of my invention resides in the process wherely I combine the two nitrates so as .to avoi the objectionable kindling properties of the sodium nitrate and to secure enhanced explosive properties in compositions in which they are ingredients. 'lhere advantages are secured by bringin the two nitrates into-minute, intimate and adhesive contact through melting.

It is well known that certain-mixtures of the two salts melt at lower temperatures than the melting temperature of either of the two salts and that an eutectic'point is found at or about 120 C. for the mixture containing four parts of ammonium nitrate and one part of sodium nitrate. At 170 C which is above its melting point, the ammonium nitrate forms the preponderating'bomponcnt of all fused mixtures of, the two salts. Furthermore, since ammonium nitrate begins to decompose at temperatures even lower than its melting point (169.6 (1.), it is evident thot a 50-50 percentage composi tion of the two salts, or mixtures containing timacy of contact of the completely fused .giixtures, can be manufactured by the here- .stantially to 160 in disclosed process.

For example, to manufacture a blend containingthese salts in equal weight, I take tylo parts of dry powdered ammonium ni trace and one part of dry powdered sodium nitrate and melt them completelyas possible at a temperature substantially not to exceed 160 (h, then l add one other part of the sodium nitrate to the "fused mass and, while stirring, bring the temperature sub The sludge thus formed cooled as rapidly possible, for example, by pouring in thin layers onto concrete or metal slabs. The hard cooled mass neiit ground to a powder and incorporated once with the other ingredients of the exiilosive composition. In preparing this blend the preponderating mass of the smliuin nitrate, in a state of minute subdivision, is imbedded in a matrix of the two salts which had been melted and quickly smiled. VVhen'the cool mass, which is substantially an oolitic conglomerate, is ground to a powder, or when this powder is remelted and ropowdered, each particle, or substantially each particle, is observed under microscope to contain both of the nites in intimate and adhesive contact. The effect of this n'iinuteness and intimacy that ammonium nitrate gives off gas at such a rate that segregation by melting of lac particles of sodium nitrate is prevented, in. other Words, besides yielding oxygen and explosive power, the ammonium nitrate functions an atoinizing agent for sodium nitrate during the moment of detonation, iIig rise to interiningling of gaseous and liquid phases and producing frothing and foaming; effects which accelerate the explosion. Further advantages obtained by this process of blending, are insensitiveness to wards simple combustionand progressiveness of explosion.

Experiments with Water added to the salts to increase their fusiloility yielded masses that were dillicult to dry and were hopelessly insensitive towards detonation, hence thc necessity of fusing only dry PCYW- dered salt was demonstrated. Other experiments, therein the salts were heated long at temperatures above 160 C., yielded inferior products, hence the lower favorable range of temperatures. substantially 125 to 160 (1., was domonstrated. lVhen the.

-melted mixtures were permitted to cool slowly or in thick layers, undesirably largo interior crystals formed of rapid solidification ther by chilling. by

spraying. or by pouring in thin layer, was

. hence the necessity masses demonstrated. l Vhen blends containing very largely preponderating masses of sodiuni nitrate are to be manufactured, as for example, when four parts of sodium ni .tral'e are combined with one part of ainnlo toluene and then wood meal so that the pew centages of composition will he as follows:

Sodium nitrate 38 Ammonium nit-rate H 38 Wood meal c. 19 Nitrotoluene 5 This powder was found to he of good cliensity for loading of cartridges and was very ellective in stump blasting.

Other effective compositions can pared in the following percentages position:

Sodium nitrate Ammonium ultra-te M "Wood meal in; 2O 18 Nitroglycerine c '1 ll '1 10 W'ood meal impregnated with ammonium nitrateunh ll) From these examoles, it is clear, that a great variety of explosive compositions can be manufactured from the blended salt-s. In general, all nitro organic compounds commonly used in. powders, also Wood ineal impregnated with ammonium nitrate by my prior process (U. 55. "Pat. No. l, i ll,59 l-), can he used to sensitize mixtures of the blends present with couihustihles such as wood meal charcoal, starch, etc.

All of these compositions, involving as they do the manufacture of the blend by the heroin disclosed nrocess and the blend itself as an ingredient thereof. are held to fall within the scope of my claims.

I claim:

1. The proc of maiuiiacturiug coir glomcrate masses of ammonium nitrate and sodium nitrate for ex ilosive purposes. which comprises changing by application of heat mir'rtnres of to sludges and then cooling rapidly to uniform conglomerates which areto he pulverized. I

53. The process of manufacturing conglomerate masses oi? an unonium nitrate and sodium nitrate for Y which comprises the partial melting of their mixtures the rapid cooling and pulvei izing: of the product thereof. 7

I 3. process of manufacturing com ernlosive. our oses conglomerates of ammonium nitrate and 'sodium nitrate for ex )losive purposes which comprises melting mixtures of the two powdered salts in the presence of a further and preponderating mass of sodium nitratetoo great to be melted at the temperature used.

The process of manufacturing adhesive blends of. ammonium nitrate and sodium nitrate t'or explosive purposes which comprises heating mixtures of the dry powdered nitrates so as to obtain substantially the greatest fluidity of the sludge and then stirring and cooling so as to obtain substantially uniform conglomerates.

6. The rocess of manufacturing adhesive blends ot ammonium nitrate and sodium nitrate for explosive purposes which comprises melting all of the ammonium nitrate and part of the sodium nitrate While the preponderating mass of sodium nitrate is present in a state of line subdivision, so that. subsequent rapid cooling will incor om-ate the unmelted powdered sodium nitrate in a ma mix of the two fused salts.

7. The process of manufacturing adhesive blends 01 ammonium nitrate and sodium nitrate for explosive purposes which comprises heating mixi-i s of said salts at 125-160 0., rapidly cc )ling its sludge and on dering its conglomerate thus formed.

8. The process of manufacturing adhesive blends of ammonium nitrate and sodium nitrat or explosive purposes which coming. 7. ting mixtures of the dry pulven ized nitrates at l25-l60 (1., then stirring and pouring onto cooling slabs in thin layers, so that rapid cooling of thesludges will substantially prevent the formation in the conglomerates of large interior crystals.

Q. "be process of manufacturingiadhcsive blends of ammonium nitrate and sodium nitrate for explosive purposes which com prises heating mixtures of t-l parts of pulverized ammonium nitrate with 1-4 parts of dry pulverizcd sodium nitrate at 125 160 so as to obtain substantially the maximum possible fusion of" the two salts, then, While stirring so as to prevent settl ng of the unniclted sodium nitrate, pouring rapidly in thin layers onto cooling slabs so and finally pulas to obtain rapid cooling,

masses thus verizing the conglomerate formed.

1.0. The process of manufacturing ad hesive blends of ammonium nitrate and sodium' nitrate for explosive purposes,-which comprises heating, cooling and pulverizin -the salts, substantially as described, an

then repeating the heating, cooling and pulverizing. I r

11. As an ingredient for expiosive purposes, eutectic mixtures of am onium nitrate and sodium nitrate, manufactured substantially as described. j v

12. As an ingredient for explosive pur-' poses, adhesive blends of ammonium nitrate and sodium nitrate, manufactured substaru tially as described. m

13, As an ingredient for explosive pur- I poses, minute particles of unmelted sodium nitrate adhering to minute particles com;

posed of melted mixtures of ammonium nitrate and sodium nitrate, manufactured substantially as described.

14. As an ingredient for explosive purposes, adhesive blends of ammoniiim nitrate and sodium nitrate, manufactured as described and possessing explosive properties substantially different from mere mechanical mixtures of the same.

15. As an ingredient for explosivclpuu poses, adhesive blends of ammonium nitrate and sodium nitrate, manufactured by melting mixtures of the dry powdered salts, in the presence of a preponderatiug mass of unmelted sodium nitrate, by cooling rapidly so as to form an uniform conglomerate of the materials, and by pulv'erizing 16, As an ingredient for explosive compositions,. adhesive blends of ammonium.

monium nitrate and l4 parts ol sodium nitrate, by cooling rapidly so as to form a uniform conglomerate of the materials, and

by pulverizing.

18. As an ingredient for explosive com ill? positions, adhesive blends of ammonium ni tratc and sodium nitrate, manufactured by melting at 125460" (1., 4l parts of ammonium nitrate and 1-4 parts of sodium nitrate, by cooling rapidly so as to form a uniform conglomerate of the materials, and by pulverizing, the product thus formed to be remelted at 12516() CL, rapidly cooled and repowlered.

In testimony that I claim the foregoing, I hereto set my hand, this 8th day of October, 1924.

\VILLIAM M. DEHN. 

